When it is fully energized and operational, Enel Green Power (EGP) North America's 250 MW Buffalo Dunes wind farm, located in Kansas, will become the largest U.S. wind project to come online in 2013, according to the American Wind Energy Association.

The $400 million wind farm will be powered by 135 GE 1.85 MW wind turbines (with an 87-meter rotor) and is expected to employ 20 full-time staff.

The wind farm was developed by Lenexa, Kan.-based TradeWind Energy and later sold to EGP. Buffalo Dunes marks the sixth wind project developed by TradeWind and sold to EGP.

Besides coming online in a year in which few new wind farms were built, several aspects of the Buffalo Dunes wind farm are notable.

For example, Alabama Power Co., a subsidiary of Southern Co., has agreed to buy the wind farm's output over 20 years. Interestingly, the power purchase agreement (PPA) provides for the "wheeling" of energy from southwestern Kansas to the Southern Company/Entergy transmission interface.

According to TradeWind, the output will flow through both the Southwest Power Pool and Entergy's Arkansas-Missouri transmission system, where it will be delivered to Southern Co.'s transmission interface. Alabama Power is then responsible for moving the energy to its local utility system.

The project has an approximately 22-mile 345 kV transmission line that connects the project's collection substation at the wind farm to the interconnection point with the main high-voltage transmission system. The interconnection point is at the existing SPS Finney Substation located near Sunflower Electric Cooperative's Holcomb coal plant.

According to Frank Costanza, TradeWind's executive vice president, the PPA is beneficial for all. The utility wanted additional low-cost Midwestern wind energy, and TradeWind had a project - and the critical firm transmission paths available and ready to go.

"Buffalo Dunes is a great example of TradeWind, EGP and the local utility communities working together," notes Costanza. "The result is a significant, job-creating economy -boosting wind project for Kansas and an inexpensive renewable wind energy for ratepayers in Alabama: a win-win for both regions of the country."

Challenges

According to Brice Barton, project development manager, the construction phase was not without its challenges. For starters, the location sits near the Sandsage Prairie, a declining habitat comprised of low-rolling sand dunes and stream breaks. Therefore, TradeWind took great pains to avoid unnecessary disturbances of the landscape.

Barton says impacts from the project disturbed fewer than 55 acres of native habitat for 22 miles of project transmission line. TradeWind also took great pains to move the turbines, roads and substation away from the protected area.

Being near the Prairie's sandy soils also impacted the wind farm's foundation design. According to a RES Americas spokesperson, the foundation design challenges at Buffalo Dunes were exceptional. The silty sands and clays impacted the foundation design significantly. To accommodate the terrain, RES Americas employed proven ground modification techniques, such as over-excavation and replacement, to densify the bearing soils and stiffen the turbine foundations.

And due to radar concerns from the Department of Defense (DoD), TradeWind changed the layout of Buffalo Dunes to keep away from a radar installation east of the project bounds.

"We developed a plan to coexist," explains Barton. "We came back to them with different proposals for an array that worked."

Once finalized, Barton says, the DoD Energy Siting Clearinghouse gave it approval to the Federal Aviation Administration, which then issued the wind farm a determination of no hazard.

With the completion of Buffalo Dunes, TradeWind will surpass the company's 1 GW mark for wind farms developed and constructed.